In recent years, hybrid vehicles, electric vehicles and fuel cell vehicles have gained significant attention as environmentally friendly vehicles.
A hybrid vehicle has, as a power source, a conventional engine and in addition thereto a DC power supply, an inverter and a motor driven by the inverter. More specifically, the engine is driven to obtain power and the DC power supply also provides DC voltage which is in turn converted by the inverter to alternate current (AC) voltage employed to rotate the motor to obtain power. For such vehicle a plurality of components are housed in a single case to miniaturize a power supply system supplying DC power.
Japanese Patent Laying-Open No. 2002-078230 discloses a portable power supply device compact and enhanced in portability. This portable power supply device allows a solar cell-equipped portable hybrid power supply system to have a secondary battery, an electric dual layer capacitor, and a DC-DC converter integrated together for miniaturization.
Japanese Patent Laying-Open No. 2002-078230 discloses a low-voltage, portable hybrid power supply, and there is room for improvement in miniaturizing a vehicular power supply system that utilizes high voltage.
When passive safety is considered, it is important that a vehicular power supply device has its power supply unit housed in a single case and thus packed in one. More specifically, it is necessary to have a high voltage power storage device with a high voltage portion packed in one so that in a collision, positive and negative high voltage cables are disconnected at a relay from the high voltage portion.